Geoffrey Lean is Britain's longest-serving environmental correspondent, having pioneered reporting on the subject almost 40 years ago.

Will the Friends again become worthy foes?

Keeping watch: FoE activists protest against the Common Agricultural Policy at EU headquarters in Brussel

"Good gracious” exclaimed the newly retired ambassador, surveying my bald pate. “It’s Geoff Lean, isn’t it? We last saw each other when we exposed the illegal selling of a tiger skin in 1979.”

Thursday evening was that kind of an occasion. Friends of the Earth – which I have been covering since its formation in 1970 – was, rather belatedly, celebrating its 40th anniversary in a fashionable but forbidding London nightclub, and hundreds of its former campaigners were staging noisy mini-reunions with each other and with a few long-standing outsiders, like me.